1. Field of the Invention
The present invention relates to an apparatus for manufacturing a dried web of paper from stock. More particularly, the present invention relates to an apparatus in which the web is positively supported during passage through the apparatus from the forming section to the dryer section.
2. Information Disclosure Statement
With the increased demand for paper and board, there exists not only a need for increased paper width production but also an increase in the actual speed at which a paper machine will operate.
More specifically, although it is possible to increase the width of a paper machine so that more tonnage per year can be produced, there exists a theoretical limit to the width of a papermaking machine. Various roll deflection compensating arrangements have been proposed which endeavor to compensate for the relative bowing between cooperating press rolls and the like. However, when cross-machine widths above 40 feet are employed, such compensation is difficult to control.
Accordingly, there has existed a trend towards increased machine speed such that machine speeds up to 10,000 feet per minute are contemplated.
In conventional papermaking machines, which operate at approximately 1,000-4,000 feet per minute, the existence of open draws has presented relatively few problems. However, as machine speeds increase, the provision of an open draw between the press section and the dryer section has introduced problems in that the relatively fragile web emerging from the press section tends to flutter during transfer from the press section into the dryer section.
Furthermore, in the event of web breakage, traditionally, the sheet is removed from the dryer section and a tail of the web is cut upstream relative to the press section. Such tail must then be manually or semi-automatically threaded from the press section into the dryer section.
Accordingly, there has existed the need of a papermaking machine having no open draw between the press section and the dryer section so that web flutter is inhibited and so that a tail can be automatically threaded into the dryer section.
Therefore, it is a primary objective of the present invention to overcome the inadequacies of the prior art devices and to provide an apparatus which makes a considerable contribution to the art of manufacturing a dried web of paper from stock.
Another object of the present invention is the provision of an apparatus which includes a forming section and a press section disposed downstream relative to the forming section. The press section includes an extended nip press having a bearing blanket which movably extends through the pressing section, the blanket cooperating with a suction pick-up roll to form a first press such that the formed web is transferred from a press felt to the blanket, the web thereafter extending through the pressing section for removing more water from the web.
Another object of the present invention is the provision of an apparatus which includes a dryer section disposed downstream relative to the press section, the dryer section including a rotatable dryer having a heated surface which cooperates with the blanket such that the pressed web is transferred from the blanket to the heated surface of the dryer.
Another object of the present invention is the provision of an apparatus in which the dryer section includes a dryer felt which extends around a portion of the heated surface, the portion being disposed downstream relative to the blanket such that the web is sandwiched between the dryer felt and the dryer.
Other objects and advantages of the present invention will be apparent to those skilled in the art by a consideration of the detailed description contained hereinafter taken in conjunction with the annexed drawings.